Section 10 Navigation and manoeuvring systems
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Naval Ships, January 2023 - Volume 2 Machinery and Engineering Systems - Part 9 Electrotechnical Systems - Chapter 3 Electrical Power Distribution and Equipment - Section 10 Navigation and manoeuvring systems

Section 10 Navigation and manoeuvring systems

Parent topic: Chapter 3 Electrical Power Distribution and Equipment

10.1 Steering gear

10.1.1 The requirements of Vol 2, Pt 9, Ch 3, 10.1 Steering gear 10.1.2 are to be read in conjunction with those in Vol 2, Pt 6, Ch 1, 7 Electrical power circuits and equipment.

10.1.2 Two exclusive circuits, fed from the main source of electrical power and each having adequate capacity to supply all the motors which may be connected to it simultaneously, are to be provided for each electric or electrohydraulic steering gear arrangement consisting of one or more electric motors. One of these circuits may pass through the emergency switchboard, if installed, see also Vol 2, Pt 6, Ch 1, 7 Electrical power circuits and equipment.

10.1.3 The main and auxiliary steering gear motors are to be capable of being started from a position on the navigating bridge and also arranged to restart automatically when power is restored after a power failure.

10.1.4 The motor of an associated auxiliary electric or electrohydraulic power unit may be connected to one of the circuits supplying the main steering gear.

10.1.5 Only short circuit protection is to be provided for each main and auxiliary steering gear motor circuit.

10.1.6 Where specified and agreed by the Naval Authority, in ships of category NS3, if an auxiliary steering gear is not electrically powered or is powered by an electric motor primarily intended for other services, the main steering gear may be fed by one circuit from the main switchboard. Consideration would be given to other protective arrangements other than described in Vol 2, Pt 9, Ch 3, 10.1 Steering gear 10.1.5 for such a motor primarily intended for other services.

10.1.7 Each main and auxiliary steering gear electric control system which is to be operated from the navigating bridge is to be served with electric power by a separate circuit supplied from the associated steering gear power circuit, from a point within the steering gear compartment, or directly from the same section of switchboard busbars, main or emergency, to which the associated steering gear power circuit is connected. Each separate circuit is to be provided with short circuit protection only.

10.2 Thruster systems for steering

10.2.1 Where azimuth or rotatable thruster units, used as the sole means of steering, are electrically driven the requirements of Vol 2, Pt 4, Ch 3, 7 Electrical systems are to be complied with.

10.3 Thruster systems for manoeuvring

10.3.1 Where a thruster unit is fitted solely for the purpose of manoeuvring, and is electrically driven, its starting and operation is not to cause the loss of any Mobility systems or Ship Type systems.

10.3.2 In order to ensure that the thruster system is not tripped inadvertently whilst manoeuvring the ship, overload protection in the form of an alarm is to be provided for the electric motor and any associated supply converters, in lieu of tripping.

10.3.3 The thruster unit electric motor is not to be disconnected as part of a load management switching operation.

10.4 Navigational aids

10.4.1 Navigational aids are to be fed from the emergency source of electrical power. See also Vol 2, Pt 9, Ch 2, 5.2 Emergency source of electrical power 5.2.7.(d).(ii).

10.4.2 For ships with navigational arrangements of one watchkeeper, navigational aids are to have an alternative supply fed from the main source of electrical power, independent of the emergency switchboard, with automatic change-over facilities.

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